论文部分内容阅读
研究了双相组织ＴｉＡｌ合金在温度为９５０～１０７５℃， 应变速率为２×１０－ ４ ～８×１０－ ５ １／ｓ的超塑性行为。结果表明，该合金在上述条件下表现出良好的超塑性，拉伸延伸率最高达到４６７％ 。在温度高于１０２５℃及应变速率不大于７×１０－ ５ １／ｓ 时，应变速率敏感指数均高于０５，最大值为０８以上。该合金超塑性变形的表观激活能为３４５ ｋＪ／ｍ ｏｌ， 在９５０℃双相ＴｉＡｌ合金的超塑性与动态再结晶有关； 而在１０００℃以上ＴｉＡｌ合金在超塑性变形过程中组织稳定， 其超塑性来源于晶界的滑动。
The superplastic behavior of dual phase TiAl alloy at 950 ~ 1075 ℃ and strain rate of 2 × 10-4 ~ 8 × 10-5 1 / s was studied. The results show that the alloy shows good superplasticity under the above conditions, the tensile elongation up to 467%. When the temperature is higher than 1025 ℃ and the strain rate is not more than 7 × 10-5 / s, the strain rate sensitivity index is higher than 05 and the maximum value is above 08. The superplastic deformation of the alloy has an apparent activation energy of 345 kJ / mol. The superplasticity of the dual-phase TiAl alloy at 950 ℃ is related to the dynamic recrystallization. However, the microstructure of the TiAl alloy is stable during the superplastic deformation at 1000 ℃, Superplasticity comes from the sliding of grain boundaries.